Eukaryotic organisms are widely used in industry as host cells for producing polypeptide for, e.g., pharmaceutical and industrial applications. The ability to manipulate gene transcription and expression gives the basis for providing higher production yields.
Conventionally, maximal expression of a gene in a eukaryotic organism is achieved by amplifying in the chromosome an expression cassette containing a single promoter operably linked to a gene encoding the polypeptide of interest and an amplifier selective marker.
Upstream from a structural gene encoding a polypeptide of interest there is a DNA sequence region (normally referred to as the promoter region) to which RNA polymerase binds. The RNA polymerase catalyses the assembly of the mRNA complementary to the appropriate DNA strand of the polypeptide coding region. Most “promoter regions” comprise a RNA polymerase recognition site (often a TATA box) located upstream from the start of the coding region (structural gene) and the site for accurate initiation of transcription.
Modification in the “promoter region” may result in enhanced transcription levels, which again may lead to increased expression and production yields.